Circuit Description
A secondary air injection (AIR) pump is used on this vehicle to lower tail pipe emissions on start-up. The powertrain control module (PCM) supplies a ground to the AIR pump relay, which energizes the AIR pump and the AIR solenoid valve. Engine vacuum is applied to the AIR Shut-off valve when the AIR solenoid is energized. The engine vacuum opens the AIR shut-off valve which allows air to flow to the exhaust manifolds.
The PCM monitors the HO2S voltages to diagnose the AIR system.
During the AIR test, the PCM activates the AIR pump during Closed Loop operation. When the AIR system is activated, the PCM monitors the heated oxygen sensor (HO2S) voltages and short term fuel trim values for both banks of the engine. If the AIR system is operating properly, the HO2S voltages should go low and the short term fuel trim should go high.
If the PCM determines that the HO2S voltages for both banks did not respond as expected during the tests, DTC P0410 sets. If only one sensor responded, the PCM sets either a DTC P1415 or P1416 to indicate on which bank the AIR system is inoperative.
Conditions for Running the DTC
| • | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0151, P0152, P0153, P0154, P0155, P0157, P0158, P0160, P0161, P0171, P0172, P0174, P0175, P0300, P0440, P0442, P0446, P0506, or P0507 are not set. |
| • | The engine run time is more than 15 seconds after closed loop operation. |
| • | The engine load is less than 33 percent. |
| • | The engine air flow is less than 20 g/s. |
| • | The engine speed is more than 750 RPM. |
| • | The ignition voltage is more than 11.7 volts. |
| • | The air/fuel ratio is 14.7:1. |
| • | The ECT is between 2°-110°C (35°-230°F). |
| • | The IAT is between -10° and +100°C (+14° and +212°F). |
| • | The fuel system is not operating in power enrichment or deceleration fuel cut-off. |
| • | The startup ECT is below 80°C (176°F). |
| • | The vehicle speed is more than 15 km/h (25 mph). |
Conditions for Setting the DTC
| • | The HO2S voltage does not go below 222 mV for 1.2 seconds or more. |
| • | The short term fuel trim does not go above a predetermined amount. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
Important: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
| • | Casting flash in the exhaust manifold may restrict the amount of air flow necessary to affect the HO2S voltage. If you suspect this, remove the air pipe from the manifold and inspect the passage. |
| • | Using the Freeze Frame/Failure Records may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame/Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same Freeze Frame conditions that you observed in order to isolate when the DTC failed. Duplicate conditions such as the following: |
| - | RPM |
| - | Load |
| - | Vehicle speed |
| - | Temperature |
| • | For an intermittent condition, refer to . |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference | ||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | Go to | ||||||||
2 |
Important: Before proceeding with this diagnostic table ensure that the AIR pump is operating and that air is present at the outlet of the AIR shut-off valve. If the AIR pump is inoperative and no air is present at the outlet of the AIR shut off valve, refer to for further diagnosis.
Does the HO2S voltage drop below the specified value? | 350 mV | Go to Diagnostic Aids | Go to Step 3 | ||||||||
Did you find and correct conditions? | -- | Go to Step 8 | Go to Step 4 | |||||||||
4 |
Is air present at the hose outlet? | -- | Go to Step 7 | Go to Step 5 | ||||||||
5 | Repair the restriction or blockage in the applicable bank AIR hoses and pipes, between the exhaust manifold and the point where the system branches to both sides of the engine. Is the action complete? | -- | Go to Step 8 | -- | ||||||||
6 | Repair the condition found. Is the action complete? | -- | Go to Step 8 | -- | ||||||||
7 | Replace the appropriate check valve. Refer to . Is the action complete? | -- | Go to Step 8 | -- | ||||||||
8 |
Does the DTC run and pass? | -- | Go to Step 9 | Go to Step 2 | ||||||||
9 | With the scan tool review the Stored Information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go t | System OK | ||||||||
